App logs, client settings, NavMenu layout

- Add real-time app logs via SignalR (log level, category filters)
- Add filters modal with restore defaults; sentinel for empty arrays
- Add client settings: max lines and auto-scroll per log panel
- Improve NavMenu: align settings + hamburger, smaller mobile logo
- LogsService, LogsHub, LoggingController, AppLogsLoggerProvider
- Persist log level and filters to appsettings.Overrides.json

docker-compose.test.yml

@@ -26,6 +26,8 @@ services:
       # Simulated systemctl status + real logs (dnsmasq logs to /data/dnsmasq.log via log-facility in dnsmasq-test.conf)
       Dnsmasq__StatusShowCommand: "/app/dnsmasq-status.sh"
       Dnsmasq__LogsCommand: "tail -n 100 /data/dnsmasq.log 2>/dev/null || echo '(no log file yet)'"
+      # Persist runtime log level across container restarts
+      RuntimeOverrides__FilePath: "/data/appsettings.Overrides.json"
     volumes:
       - ${TESTDATA_MOUNT:-./testdata-mount}:/data
     networks: